It was useful for debug to see file descriptors for each event. Before:
$ perf stat -vvv -e cycles,cache-misses ls ... sys_perf_event_open: pid 12146 cpu -1 group_fd -1 flags 0x8 ... sys_perf_event_open: pid 12146 cpu -1 group_fd 3 flags 0x8 sys_perf_event_open failed, error -13 Now: $ perf stat -vvv -e cycles,cache-misses ls ... sys_perf_event_open: pid 12858 cpu -1 group_fd -1 flags 0x8 = 3 ... sys_perf_event_open: pid 12858 cpu -1 group_fd 3 flags 0x8 sys_perf_event_open failed, error -13 Link: http://lkml.kernel.org/n/tip-7drsvjamul8bawh8ga1vp...@git.kernel.org Signed-off-by: Jiri Olsa <jo...@redhat.com> --- tools/perf/util/evsel.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index e58a2fbf3b16..b2365a63db45 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1481,7 +1481,7 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, group_fd = get_group_fd(evsel, cpu, thread); retry_open: - pr_debug2("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx\n", + pr_debug2("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx", pid, cpus->map[cpu], group_fd, flags); FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr, @@ -1490,11 +1490,13 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, group_fd, flags); if (FD(evsel, cpu, thread) < 0) { err = -errno; - pr_debug2("sys_perf_event_open failed, error %d\n", + pr_debug2("\nsys_perf_event_open failed, error %d\n", err); goto try_fallback; } + pr_debug2(" = %d\n", FD(evsel, cpu, thread)); + if (evsel->bpf_fd >= 0) { int evt_fd = FD(evsel, cpu, thread); int bpf_fd = evsel->bpf_fd; -- 2.7.4
